This invention relates to photographic processing apparatus and is more particularly concerned with the application of photographic processing solutions to the material to be processed.
It is known to apply processing solutions to the material by passing the material through a number of tanks or reservoirs containing the required solutions. Such arrangements require large volumes of processing solutions in order to operate effectively. This means that the processing solutions used need to be stable for relatively long periods of time.
To overcome the necessity of maintaining large tanks of relatively unstable solution further methods were developed in which the solutions are applied to the surface of the material being processed. In this method the processing chemicals required can be kept separately until just before they are needed.
There are however disadvantages with surface application. The chemicals are static on the surface of the material being processed. There is thus no agitation and so chemical activity is low. xe2x80x9cInstant seasoningxe2x80x9d effects cause halide build-up and slows down the processing. It is difficult to achieve uniformity due to the limited amount of processing solution which is being applied to the material. Furthermore, the usage rates of the processing chemicals is high as there is substantially no sideways mixing of chemicals on the surface of the material.
It is an object of the invention to provide a method and apparatus which overcomes the problems mentioned above.
According to the present invention there is provided a method of processing light sensitive material by the surface application of processing solution wherein fresh processing solution is applied to the surface of a moving belt by means of an applicator and the material to be processed is brought into moving surface contact with the moving belt, the resulting relative motion providing a high level of agitation and mixing of the processing solution.
Preferably, either or both of the processing solution and the material is heated prior to contact with the belt. The applicator may be movable. This enables either counter current or co-current processing.
The invention further provides an apparatus for processing light sensitive material, the apparatus comprising a flexible belt,
first drive means for driving the belt,
at least one applicator for applying fresh processing solution to the surface of the belt, and
second drive means for transporting the material to be processed in contact with the surface of the belt and at a slower speed than the belt, the resulting relative motion providing a high level of agitation in the processing solution.
The method provides very high agitation and allows the use of a higher temperature than is practical in conventional tanks. Processing is therefore more rapid than in prior art processes. Chemical usage is economical because the method applies replenisher at low rates to the paper surface. As stated, the method can be counter-current, which is preferable for washing, or co-current, which is preferable for development. It is possible to change a single stage of the process from one type to another by changing the applicator. The method is ideal for unstable processing solutions such as those used for RX or RedoX amplification processing.